December 19, 2017

India’s Arighat Prototype Limited by Reactor Power & Missile Maturity

India’s 6,000 tonne INS Arighatprototype SSBN launch on
November 19, 2017 is less of a surprise when one considers GhalibKabir’s advice
on December 12, 2017 that INS Arihant
and another 6,000 tonne nuclear sub (now known as Arighat) were under
construction since 2006. Their reactor specifications were apparently frozen at
83MW, meaning they could not be built much larger than 6,000 tonnes - if a cruising speed around 20kt was maintained. India, of course, sees its future SSBNs as the most secure second strike weapon platforms.

Perhaps the need for a
continual high level of SSBN budgetary funding prompted Indian SSBN builders to
disseminate larger SSBN Aridhaman propaganda for years. Propaganda could also be seen as public
relations. As early as July 14, 2014Aridhaman
was to be “launched into water soon”. Submarine Matters as early as August 24, 2014doubted the ambition of India's SSBN and 6 x SSN programs (SSNs sanctioned in February 2015).

So the non-appearance of a much larger INS Aridhaman SSBN may be due to India’s
current inability to produce a reactor much more powerful than 83MW. Another
limitation seems to be the immaturity of any 7,000km range SLBM (called K-5 or K-6). So
India is not indulging in a rush program to produce a 13,000 tonne SSBN large
enough to mount K-6s.

India’s SSBN Program at its most basic seems to have several
requirements including sufficient reactor
power, SSBN size to accommodate
large enough SLBMs to carry a
sufficient payload over a sufficient range. More specifically:

B.launch 2 small 7,000 tonne SSBN by 2022
which will have 8 x (very limited 3,500km range K-4s) 1.3m diameter, 10m long. India, of course, claims to, or does, pursue a No First Use nuclear policy. But if China fired first the medium range K-4 can, once it is ready, reach only a limited number of significant targets within
China. These include:

For a 7,000 tonne SSBN it is preferable
to use a slightly uprated 90 MW reactor. This is possible, assuming 6,000 tonne
Arihant of 83MW reactor is a development of the Russian 70MW - 90MW VM-4 reactor. According to Dinesh Kumar, December 30, 2017 "

INS Arihant has its limitations...[Arihant's and Arighat's (?)] nuclear reactor has a short refuelling cycle and therefore a limited endurance capacity." If ArHydronamic improvements can be made to the sail/fin
and pump jet propulsor or a slower cruising speed may be acceptable.

and/or

C.skip the 7,000 tonne SSBNs and go
straight to 13,500 tonne SSBNs powered by an Indian-Russian development of Russia’s well
used Russia
190 MWt OK-650 reactor. A 13,500 tonne SSBN needs the
capability to launch, from Bay of Bengal bastion waters, a true 7,000km
intercontinental SLBM with warheads in range of Beijing. Specifically 12
x K-6 SLBMs, 12m
long, 2m diameter. A mature K-6 would give India an equivalent capability to China's JL-2 SLBM (with a range up to 8,000km).

Maybe the above US SLBM comparitive image is useful if K-4 can be equated to a light warhead Polaris A2 and the K-6 equated to a Trident I C4. This would mean the K-6 would be over twice the overall K-4 SLBM weight. (Image and broader data is at the FAS website).

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SLOW INDIAN SSBN PROGRAM?

India may not need to develop SSBNs at a cracking US vs
Soviet Union Cold War pace because India's main SSBN opponent, China, is not developing SSBNs quickly. This is as far as overt sources can know. Also one must remember China launched the first of its nuclear submarines (Type 091s) in 1970.

I agree with Dinesh Kumar, December 30, 2017 analysis, that India's only operational SSBN Arihant "with a limited missile range compares very modestly with
China, which already has about ten nuclear-powered submarines and that too with
greater endurance and long-range nuclear tipped missiles, in addition to over
50 conventional submarines. China is expected to increase its submarine fleet
to between 69 and 78 by 2020, according to a US Congress report. Both Pakistan [8 future SSKs] and Bangladesh [2 renovated SSKs] have contracted purchase of conventional submarines from China,
thus adding to India’s increasing security challenge in the Indian Ocean
Region."

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